Sensation evoked by bipolar intrapulpal stimulation in man.

Bipolar intrapulpal stimulation was applied to human teeth using the same procedure as in animal experiments. The effects of variation of stimulus parameters on the quality of sensation were studied. A prepain sensation exists which cannot be explained by diffusion of the stimulus to periodontal tissues. When the intensity of stimulation is increased, the prepain sensation is gradually replaced by a pinprick sensation. With long, high intensity stimulation, an acute long lasting very painful sensation appears. To evoke a pinprick sensation the best stimulation seems to be a 50 msec train (0.5 msec, 300 Hz, 0.5 mA). Longer train duration and a higher intensity of current are necessary to evoke a long lasting, acute very painful sensation. Since the exclusively Adelta and C nerve fiber content of the dental pulp is well documented and since it is possible to avoid current diffusion outside the dental pulp cavity, the tooth pulp implantation seems to be a good technic for studying pain, as long as the investigator uses adequate stimulation.